Tests fails against Pytest4.x

[Stanislav Levin]

I got an error while running this package test suite against Pytest4.x:

python setup.py test -v -a '--cov sphinxjp'

running test
running egg_info
deleting src/sphinxjp.themes.revealjs.egg-info/requires.txt
writing src/sphinxjp.themes.revealjs.egg-info/PKG-INFO
writing namespace_packages to src/sphinxjp.themes.revealjs.egg-info/namespace_packages.txt
writing top-level names to src/sphinxjp.themes.revealjs.egg-info/top_level.txt
writing dependency_links to src/sphinxjp.themes.revealjs.egg-info/dependency_links.txt
writing entry points to src/sphinxjp.themes.revealjs.egg-info/entry_points.txt
reading manifest file 'src/sphinxjp.themes.revealjs.egg-info/SOURCES.txt'
reading manifest template 'MANIFEST.in'
warning: no files found matching '*.png' under directory 'src'
warning: no files found matching '*.svg' under directory 'src'
warning: no files found matching '*.otf' under directory 'src'
writing manifest file 'src/sphinxjp.themes.revealjs.egg-info/SOURCES.txt'
running build_ext
Traceback (most recent call last):
  File "setup.py", line 97, in <module>
    zip_safe=False
  File "/usr/lib/python2.7/site-packages/setuptools/__init__.py", line 145, in setup
    return distutils.core.setup(**attrs)
  File "/usr/lib64/python2.7/distutils/core.py", line 151, in setup
    dist.run_commands()
  File "/usr/lib64/python2.7/distutils/dist.py", line 953, in run_commands
    self.run_command(cmd)
  File "/usr/lib64/python2.7/distutils/dist.py", line 972, in run_command
    cmd_obj.run()
  File "/usr/lib/python2.7/site-packages/setuptools/command/test.py", line 234, in run
    self.run_tests()
  File "setup.py", line 25, in run_tests
    errno = pytest.main(self.pytest_args)
  File "/usr/lib/python2.7/site-packages/_pytest/config/__init__.py", line 60, in main
    config = _prepareconfig(args, plugins)
  File "/usr/lib/python2.7/site-packages/_pytest/config/__init__.py", line 188, in _prepareconfig
    raise TypeError(msg.format(args, type(args)))
TypeError: `args` parameter expected to be a list or tuple of strings, got: '--cov sphinxjp' (type: <type 'str'>)